Obesity is the world pandemic of the 21st surgery in the developed world. The health risks associated are multiple, as diabetes, hypertension, hypercholesterolemia, cardiovascular disease, higher death rates from almost all types of cancers compared to normal weight, individuals leading ultimately to a shortened life expectancy of more than 10 years of life and a diminished quality of all life parameters. Bariatric surgery is considered as the best option for permanent weight loss in patients with morbid obesity (BMI > 40) or patients with a BMI > 35 with severe associated comorbidities. Nowadays, trained surgeons can offer a variety of operations to suitable candidates, the most popular of which are the adjustable gastric band, the Roux-en-Y gastric bypass and the gastric sleeve, all performed in a minimally invasive way through laparoscopy.
The adjustable gastric band is actually an inflatable silicon band placed around the stomach creating a small pouch at the upper part of the stomach. This in turns leads to early satiety as this little pouch (usually of 20 cm3) distends with a small amount of food. A port connected to the band through a tube is placed in the subcutaneous tissue within the abdominal wall. After several visits to the doctor’s office the diameter of the ring created from the band around the stomach is adjusted by instilling normal saline through the port so as to find an equilibrium between an early satiety that leads to the weight loss and the passage of food required for a healthy life. The maximum weight loss is usually achieved in a period of 3 years and is approximately 50% of the excess base weight. The pros of the adjustable gastric band is that is an operation performed almost always laparoscopicaly with a short operative time, low mortality rate (< 0.1%), low morbidity, short hospital stay (1 day), it is removable not leading to irreversible changes of the stomach as there is no cutting or stapling, does not lead to any malabsorption issues that will require a lifetime vitamin and nutrients supplementation. The complications are usually long term due to the presence of a foreign body the most serious of which is band erosion through the stomach wall and band slippage obstructing the gastro esophageal junction. The greatest default of the band is that even if it produces early satiety it does not alter the neurohormonals mechanisms of appetite and in consequence does not enter in the behavioral modification required to change the patients’ attitude towards food. It is most helpful for patients determined to change their life habits and willing to comply with post surgical diet (as for example the sweets and beverages can easily pass through the band ‘’cheating’’ the operation) and for those who actually seek is a “boost” of weight loss that will help them adopt a different lifestyle.
The Roux-en-Y gastric bypass is the creation of a small permanent gastric pouch of 25cm3 which is anastomosed with a jejuna limb (the alimentary limb) that leads to the bypass of the normal route of food from the stomach to the duodenum. Finally the intestinal continuity is restored by another anastomosis of the jejuna limb that carries the chyme from the liver and the pancreas (the biliary limb) to distal ileum. So you have a purely restrictive operation combined with a malabsorbtive component as the digestive enzymes necessary for food absorption arrive at the “crossroad” at distal ileum just before the food enters the large intestine. The weight loss is immediate and continues until 2 years after the operation. The mean excess weight loss can range from 60 – 75 % and in the same time is more sustainable compared to other procedures though it’s multiple mechanisms as apart from a restrictive and malapsorptive component there seems to be a neurohormonal component leading to a diminished appetite. The cons are that gastric bypass is a complex operation with a mortality rate of 1%, an anastomotic leak of 2% that may lead to a reoperation, a longer operative time, a mean hospital stay of 5 days, the permanent nature of the operation which leads to lifetime requirement of vitamins and supplements (such as B12, iron, calcium), and dumping syndrome when the person tries to eat sugary food as it passes directly in the intestine. Gastric bypass is best suited for patients that seek an operation that will require the least effort from their part in losing weight and seems to guarantee a permanent solution to their obesity problem even though it comes with a higher operative risk and lifetime drug supplementation.
The gastric sleeve is a relative new restrictive procedure in which the 75% of the stomach (mostly the fundus which is used in storing food) is removed leading to a small functionally active stomach with no alteration in the routing of food. The gastric sleeve surprisingly seems to work in helping patients losing weight with two additional mechanisms apart from a pure restrictive one. The first is an accelerated gastric emptying and the second is a neurohormonal mechanism mediated through the hormone grehlin that is produced from the part of the stomach that is removed. Grehlin is the hormone of hunger and resecting the fundus which is the main site of its production resolves the viscious cycle of uncontrolled appetite present in almost all obese patients. The mean excess base weight loss in 3 years is almost 60 % comparable to the gastric bypass even if there are no long term studies to confirm its sustainability. The cons of gastric sleeve is that is an irreversible operation, has a leak rate of 1-2%, is more complex than the adjustable gastric band, requires a longer operative time and hospital stay ( 3days). The pros are that is less complex when it is compared to the gastric bypass as it does not comprises any anastomosis and does not alter the normal route of food, it seldom requires any form of drug supplementation and has a mortality rate of 0,1-0.5% and finally it may be used as a first of a staged procedure for super –super obese ( BMI > 60 )patients requiring gastric bypass as a definitive procedure.